Kallitype

A chemical process similar to the Van Dyke brown based on the use of a combination of ferric and silver salts.

[1] The use of ferric oxalate allows for both extended shadow definition (higher DMAX) and contrast control.

[1] Many developing solutions can be used to give a different image color (brown, sepia, blue, maroon and black).

Ferrous ions embedded in the paper as a result of poor clearing is the cause of the lack of belief in image permanence.

While the Van Dyke Brown and Argyrotype are both "printing out" processes (with the complete image being formed during exposure), the Kallitype is a "develop out" process that requires the print to be submerged in a developer solution to make the image visible after exposure.